CALLS for help made from mobile phones can be more of a hindrance than a help to emergency services, according to research from Warwick University.

Lines that crackle or disconnect and voices that break up affect more than one in four 999 calls for an ambulance, says a study published in this week's British Medical Journal.

And the increasing ownership of mobiles can lead to switchboards becoming clogged with too many calls reporting the same incident.

Joanne Higgins, a research fellow from Warwick University, worked on a research project which analysed 1,830 calls to ambulance services.

She said: "We were trying to highlight the problems so services can be made more efficient, which is obviously going to benefit patients.

"I think some people may find it surprising that mobiles can cause difficulties. Obviously they can be enormously beneficial because callers can ring from the scene of an incident but, countering that, there can be problems with poor reception and with multiple calls.

Miss Higgins, who worked alongside other research fellows from Birmingham University, said people should try to use mobiles with more thought.

The project also reveals ambulance response staff commonly have trouble because callers are emotional and distressed. con-Higgins said: "The two key things people should tell the ambulance service when ringing are what has happened and where."